Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

077
FXUS63 KLOT 281929
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
129 PM CST Sat Feb 28 2026

.KEY MESSAGES...

- A relatively quiet pattern will continue through the weekend
  with a few snow showers today near the Wisconsin state line,
  and near the Lake Michigan shoreline tonight into Sunday.

- A period of warmer, and wetter, conditions is expected next
  week into the second full week of March.

&&

.DISCUSSION...
Issued at 129 PM CST Sat Feb 28 2026

Through Sunday Night:

It`s a rather banal day across the region with broken upper-
level cloud cover and northeasterly winds. A band of snow
continues to meander across southeastern Minnesota and southern
Wisconsin, with dry air largely limiting any meaningful
southward penetration into northern Illinois. Temperatures
across the area vary from north to south, ranging from near
freezing along the Wisconsin state line to around 50 near US-24.


Tonight, a 1035mb surface high will build into the Upper Great
Lakes and support an increase in northeasterly flow and cold air
advection down Lake Michigan. In spite of marginal inversion
heights (a consequence of the cyclonic shear axis of the upper-
level flow remaining well northeast of our area), increasing
shoreline convergence should support a gradual increase in lake-
induced stratus, flurries, and a few show showers. In all, this
set-up looks pretty darn marginal, so will only advertise a
dusting to perhaps a few tenths of an inch of snow accumulations
should bonafide snow showers actually develop. Elsewhere,
tonight will be relatively chilly with overnight lows in the
upper teens (northwest) to mid 20s (southeast).

Lake effect flurries and snow showers may continue near the
Lake Michgian shore through Sunday morning before tapering in
coverage during the afternoon as the surface high meanders
through the central Great Lakes. Partly cloudy skies and
continued northeasterly winds will otherwise define an
unremarkable day with highs generally in the 30s.

Tomorrow night looks similarly quiet with light easterly flow,
broken cloud cover, and overnight lows generally in the upper
teens to lower 20s. With the baroclinic zone expected to stall
across southern Missouri, Illinois, and Indiana, any
precipitation with the next wave propagating into the
Mississippi River Valley should miss our area.

Borchardt

Monday Onward:

A broader zonal flow regime with an embedded slow-moving trough
over the central Rockies early in the week will transition to a
much more meridional pattern highlighted by deep western
troughing for the second half of the week. Meanwhile, an
expansive Bermuda High will foster a persistent feed of Gulf and
Caribbean moisture toward the central CONUS through the period.
This will ultimately result in a seasonably mild to
unseasonably warm period with several rounds of rain and
localized convection over the area. While axes of heavy rain
appear likely over the mid-Mississippi and Ohio River valleys,
it remains to be seen where those axes set-up and whether those
axes align over the same location and result in flooding
concerns.

Initially, broad low-level isentropic ascent combined with
modest moisture transport will bring the first area of precip
over the area late Monday night into Tuesday. While rain is
favored, low-level wet-bulb temps near freezing could result in
minor impacts from light freezing rain close to the Wisconsin
state line through mid-morning.

Beyond Tuesday, the spread in the ensemble suite, owing to the
differences in the evolution of the western trough, offers less
confidence on exactly when and where heavy rain axes develop.
However, with PWATs around 1.5" (300% of normal), any pronounced
wave emanating from the western trough will induce sufficient
forcing to realize focused axes of heavy rain. As a whole, the
best focus mid to late week remains just south of the forecast
area Tuesday night.

Will also need to keep an eye on the potential for more
organized convection in or around the area late Thursday and
especially Friday as a large portion of the western trough
ejects toward the mid to upper-Mississippi River Valley.

Kluber

&&

.AVIATION /18Z TAFS THROUGH 00Z MONDAY/...
Issued at 1200 PM CST Sat Feb 28 2026

Forecast concerns for the terminals...

- Period of snow showers/flurries this afternoon, mainly near
  the IL-WI line.

- MVFR ceilings to develop this evening and persist through
  Sunday morning.

- Non-zero chance (10-15%) for lake effect flurries late tonight
  into Sunday morning.


A band of snow has developed across southern MN and WI this
morning and will continue to organize as it pivots eastward
through the afternoon. The band is expected to remain north of
our area in WI, but a few snow showers and/or flurries have been
seen across portions of far northern IL and that should continue
through the afternoon. Beneath any snow showers/flurries this
afternoon visibilities will briefly dip into the 3-4 mile range
with some MVFR clouds expected as well. The greatest confidence
for these snow showers/flurries remains near RFD but a there
remains a 20-30% chance for a couple of flurries as far south as
ORD and MDW. Regardless, little to no accumulation is expected
due to marginal surface temperatures (33-36F) and poor quality
snow.

Heading into this evening, ceilings will begin to lower into the
1500-2500 ft range over Lake Michigan and spread inland on the
northeast winds. Therefore, a period of MVFR ceilings is
expected tonight and through the morning on Sunday before skies
begin to scatter back to VFR Sunday afternoon. Additionally, a
band of lake effect snow is expected to develop tonight and
mainly impact areas near the IL-WI line, but there is non-zero
chance (10-15%) that the band could drift into the Chicago area
terminals after 09z tonight and linger through Sunday morning.
Given the low confidence on lake effect snow coverage have opted
to forego a formal mention in the TAFs but will keep a close eye
on trends.

Otherwise, expect northeast winds to prevail through the period
with speeds around 8-12 kts. Though, a few gusts around 20 kts
may be seen this evening and overnight as a surface low drifts
across the Ohio River Valley.

Yack

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 3 PM CST Sunday for Winthrop Harbor
     IL to Burns Harbor IN.

     Small Craft Advisory until 3 PM CST Sunday for Burns Harbor to
     Michigan City IN.

&&

$$

Visit us at weather.gov/chicago